From: Olivier Goffart <ogoffart@woboq.com>
Date: Fri, 12 Feb 2016 12:34:44 +0000 (+0000)
Subject: Fix ICE with constexpr and friend functions
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=26f6c2fd8a9d945be7d8f14e26ca0092abcc5ac3;p=clang

Fix ICE with constexpr and friend functions

Fix a crash while parsing this code:

  struct X  {
    friend constexpr int foo(X*) { return 12; }
    static constexpr int j = foo(static_cast<X*>(nullptr));
  };

Differential Revision: http://reviews.llvm.org/D16973

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@260675 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/AST/ExprConstant.cpp b/lib/AST/ExprConstant.cpp
index eaa61ea5c4..739649234a 100644
--- a/lib/AST/ExprConstant.cpp
+++ b/lib/AST/ExprConstant.cpp
@@ -3736,7 +3736,8 @@ static bool CheckTrivialDefaultConstructor(EvalInfo &Info, SourceLocation Loc,
 /// expression.
 static bool CheckConstexprFunction(EvalInfo &Info, SourceLocation CallLoc,
                                    const FunctionDecl *Declaration,
-                                   const FunctionDecl *Definition) {
+                                   const FunctionDecl *Definition,
+                                   const Stmt *Body) {
   // Potential constant expressions can contain calls to declared, but not yet
   // defined, constexpr functions.
   if (Info.checkingPotentialConstantExpression() && !Definition &&
@@ -3749,7 +3750,8 @@ static bool CheckConstexprFunction(EvalInfo &Info, SourceLocation CallLoc,
     return false;
 
   // Can we evaluate this function call?
-  if (Definition && Definition->isConstexpr() && !Definition->isInvalidDecl())
+  if (Definition && Definition->isConstexpr() &&
+      !Definition->isInvalidDecl() && Body)
     return true;
 
   if (Info.getLangOpts().CPlusPlus11) {
@@ -4275,7 +4277,7 @@ public:
     const FunctionDecl *Definition = nullptr;
     Stmt *Body = FD->getBody(Definition);
 
-    if (!CheckConstexprFunction(Info, E->getExprLoc(), FD, Definition) ||
+    if (!CheckConstexprFunction(Info, E->getExprLoc(), FD, Definition, Body) ||
         !HandleFunctionCall(E->getExprLoc(), Definition, This, Args, Body, Info,
                             Result, ResultSlot))
       return false;
@@ -5483,9 +5485,9 @@ bool RecordExprEvaluator::VisitCXXConstructExpr(const CXXConstructExpr *E) {
   }
 
   const FunctionDecl *Definition = nullptr;
-  FD->getBody(Definition);
+  auto Body = FD->getBody(Definition);
 
-  if (!CheckConstexprFunction(Info, E->getExprLoc(), FD, Definition))
+  if (!CheckConstexprFunction(Info, E->getExprLoc(), FD, Definition, Body))
     return false;
 
   // Avoid materializing a temporary for an elidable copy/move constructor.
@@ -5971,9 +5973,9 @@ bool ArrayExprEvaluator::VisitCXXConstructExpr(const CXXConstructExpr *E,
   }
 
   const FunctionDecl *Definition = nullptr;
-  FD->getBody(Definition);
+  auto Body = FD->getBody(Definition);
 
-  if (!CheckConstexprFunction(Info, E->getExprLoc(), FD, Definition))
+  if (!CheckConstexprFunction(Info, E->getExprLoc(), FD, Definition, Body))
     return false;
 
   if (ZeroInit && !HadZeroInit) {
diff --git a/test/SemaCXX/constant-expression-cxx11.cpp b/test/SemaCXX/constant-expression-cxx11.cpp
index 7b9d0150e1..47606b4f03 100644
--- a/test/SemaCXX/constant-expression-cxx11.cpp
+++ b/test/SemaCXX/constant-expression-cxx11.cpp
@@ -2005,3 +2005,13 @@ namespace PR24597 {
   constexpr int a = *f().p;
   constexpr int b = *g().p;
 }
+
+namespace IncompleteClass {
+  struct XX {
+    static constexpr int f(XX*) { return 1; } // expected-note {{here}}
+    friend constexpr int g(XX*) { return 2; } // expected-note {{here}}
+
+    static constexpr int i = f(static_cast<XX*>(nullptr)); // expected-error {{constexpr variable 'i' must be initialized by a constant expression}}  expected-note {{undefined function 'f' cannot be used in a constant expression}}
+    static constexpr int j = g(static_cast<XX*>(nullptr)); // expected-error {{constexpr variable 'j' must be initialized by a constant expression}}  expected-note {{undefined function 'g' cannot be used in a constant expression}}
+  };
+}